Nowadays the assembly of modern aircraft fuselages usually takes place in that a plurality of vertical frames in longitudinal direction of a fuselage are connected to a plurality of horizontal stringers that are aligned, so as to be essentially perpendicular to said vertical frames, to form a skeleton, whereupon on the outside the individual exterior skin fields of the fuselage are riveted on or bonded on. In this process the fuselage is not produced in a continuous piece; instead, at first individual fuselage sections (also known as barrels or segments) are formed, which sections are subsequently joined to form a complete fuselage tube. To separate the passenger cabin from the cargo compartment located beneath it, in the individual segments on the frames a floor grid is attached. In this known type of fuselage assembly the fuselage is thus made from a large number of individual components (frames, stringers, exterior skin fields) in a complex assembly process, as a result of which considerable costs arise already during assembly of the fuselage.
Apart from these difficulties relating to production technology, there is a further disadvantage in that both the passenger cabin and the cargo compartment, due to the low air pressure at high altitudes, have to be pressurised during the flight. It is therefore necessary that in the case of decompression (drop in pressure) in the passenger compartment or cargo compartment, which decompression can, for example, be caused by damage to the exterior skin at high altitude, rapid pressure equalisation between these two spaces occurs, because otherwise the fuselage structure can be destroyed as a result of the pressure acting unilaterally on the floor grid, which floor grid is not designed to withstand such loads. In order to ensure pressure equalisation, pressure equalisation flaps are thus normally installed on the sides of the floor along the entire length of the fuselage, which pressure equalisation flaps are, however, associated with a further disadvantage in that in the case of an emergency landing on water, water enters the entire fuselage particularly quickly by way of this connection.